Re: [PATCH v4] DSE: Fix ICE after allow vector type in get_stored_val

[Jeff Law <jeffreyalaw@gmail.com>]

On 5/2/24 7:51 PM, pan2.li@intel.com wrote:
> From: Pan Li <pan2.li@intel.com>
> 
> We allowed vector type for get_stored_val when read is less than or
> equal to store in previous.  Unfortunately,  the valididate_subreg
> treats the vector type's size is less than vector register as
> invalid.  Then we will have ICE here.
> 
> This patch would like to fix it by filter-out the invalid type size,
> and make sure the subreg is valid for both the read_mode and store_mode
> before perform the real gen_lowpart.
> 
> The below test suites are passed for this patch:
> 
> * The x86 bootstrap test.
> * The x86 regression test.
> * The riscv rv64gcv regression test.
> * The riscv rv64gc regression test.
> * The aarch64 regression test.
> 
> gcc/ChangeLog:
> 
> 	* dse.cc (get_stored_val): Make sure read_mode/write_mode
> 	is valid subreg before gen_lowpart.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.target/riscv/rvv/base/bug-6.c: New test.
OK for the trunk.  Let's let it simmer on the trunk for a while before 
we consider backporting.

jeff